Case Study
Optimised Heating and Ventilation for Food Manufacturing
Overview
Client: UK Snack Manufacturer
Industry: Food Manufacturing / Food Processing
Project Overview: Penmann delivered a heating and ventilation system for PepsiCo’s Leicester snack production site, using displacement ventilation to manage heat, maintain air quality, and meet hygiene standards. The system, supported by stainless steel AHUs, heat recovery, and a heat pump chiller, provides efficient year-round control and improved working conditions.
Part of PepsiCo, the client is one of the UK’s leading snack manufacturers. The company’s Leicester site required a new heating and ventilation solution for Bay 4, a production and packing area that presents demanding environmental challenges. Penmann was commissioned to design, supply, install, and commission a system capable of managing high internal heat loads while maintaining strict air quality and hygiene standards essential in food manufacturing environments.
Project Background
The facility contained two distinct zones: the production area, where process loads generate substantial heat, and the packing area, where stable and comfortable conditions are vital for both product integrity and workforce wellbeing. Traditional mixing ventilation methods were considered unsuitable due to the high roof volume and heat generation. Instead, Penmann proposed a displacement ventilation approach, building on experience from comparable installations and validated load estimates from existing systems in adjacent bays.
Design Approach
Displacement ventilation was selected as the most effective and efficient solution for this project. Unlike conventional mixing systems, which distribute air at higher velocities and require larger volumes of conditioned air, displacement introduces low-velocity, cooled air at floor level. This air naturally settles in the occupied zone, displacing warmer air, odours, and airborne contaminants upwards where it can be extracted.
This principle delivers two key benefits: precise temperature control in working zones and improved removal of contaminants, ensuring both product safety and staff comfort. The design also reduces the overall volume of air movement required, offering significant energy savings.
To achieve the desired performance, Penmann engineered two separate air handling units (AHUs): one dedicated to the production zone and another serving the packing area. Each AHU was designed with integral supply and extract systems, supported by a heat recovery module that captures energy from the exhaust air stream to pre-condition incoming air. This process reduces energy demand during colder months and lowers running costs.
Technical Specification
The system design parameters established strict internal conditions. The process area was to remain within 5°C of external conditions, with a nominal maximum of 25°C when ambient conditions permitted. The packing area required a tighter control range of 22°C ± 2°C.
The AHUs were linked to a high-efficiency heat pump chiller, which provided cooling during summer and reversed to deliver heating in winter. A fully insulated chilled water circuit, operating with a propylene glycol solution, ensured reliable performance under varying load conditions. Stainless steel ductwork, both internal and external, was specified for durability and hygiene, with floor-mounted displacement terminals in the process zone and suspended terminals in the packing area to deliver optimum airflow patterns.
Control of the installation was achieved through an advanced Building Management System (BMS). This system incorporated inverter-driven fans, room and duct temperature sensors, filter pressure monitoring, and fully automated valve and damper control, allowing precise regulation of conditions across both areas.
Benefits Delivered
Energy Efficiency
The displacement system required only around 65% of the air volume that a conventional mixing system would need to achieve equivalent comfort levels. This reduced fan power demand by approximately 35%, directly lowering electricity consumption and operating costs. The integration of heat recovery modules further improved efficiency by re-using waste heat from the exhaust air stream, significantly reducing the requirement for additional heating in winter.
Improved Air Quality
By delivering cooled air at low velocity directly into the occupied zones, the system created a steady upward flow pattern. Warm air, along with airborne particles and odours, was pushed away from staff and products into the extraction path. This method enhanced hygiene within the food production environment and reduced the build-up of dust and contaminants on surfaces, which in turn lowers cleaning and maintenance requirements.
Reliable Environmental Control
The installation provided a controlled environment that met the differing demands of both the production and packing areas. Staff working in high-heat conditions benefited from cooler, more stable air temperatures, improving comfort and productivity. Meanwhile, the packing area maintained consistent conditions, supporting product quality and packaging integrity.
Hygienic and Durable Construction
All internal ductwork and displacement diffusers were constructed in 304-grade stainless steel, offering a high level of hygiene compliance for a food manufacturing environment. Stainless steel construction also provides long-term durability and resistance to corrosion, ensuring the installation will perform reliably over many years of operation.
Flexible Year-Round Operation
The heat pump chiller provided both cooling and heating functions, ensuring the system was effective throughout the year. During summer, it maintained comfort by managing high internal heat gains, while in winter it acted as a supplementary heating source alongside the recovered heat energy from the AHUs. This dual capability ensured continuous efficiency regardless of seasonal conditions.
Outcome
The Bay 4 heating and ventilation project demonstrates Penmann’s expertise in designing and delivering systems for complex food manufacturing environments. By applying displacement ventilation principles, supported by advanced controls and hygienic construction, the installation has provided the client with an energy-efficient, reliable, and compliant solution.
The project improved working conditions for staff, supported high standards of hygiene and product safety, and reduced the site’s energy consumption. For the client, this investment delivered not only immediate operational benefits but also long-term value through lower running costs and system durability.